Vitamin D supplementation for patients with type 2 diabetes improves cardiorespiratory fitness and muscle mitochondria among those who are taking statins, a new RCT reveals

Researchers in India said the statin simvastatin tends to cause deterioration in exercise-mediated cardiorespiratory fitness in adults with type 2 diabetes, by blocking the synthesis of coenzyme Q10.

But their study found these negative measures can be blunted if people also take vitamin D.

"Thus, vitamin D supplementation may improve the statin-mediated changes in cardiorespiratory fitness and mitochondrial content by improving the enzymatic machinery involved in oxidative phosphorylation, which is blocked by statins,” ​they found.​

The research team, from the Post Graduate Institute of Medical Education and Research in Chandigarh, recruited vitamin D deficient diabetes patients aged 25-50 years for the trial.

They performed moderate intensity aerobic exercise for 12 weeks before being allocated into three groups to receive either the statin simvastatin (40mg once daily) plus a vitamin D placebo, simvastatin plus vitamin D (60,000 units once weekly) and vitamin D (60,000 units once weekly) plus a statin placebo.

They then measured cardiorespiratory fitness and skeletal muscle mitochondrial content.

Supplement boost

The data from the 28 participants who finished the trial showed that cardiorespiratory fitness decreased by 8.4% (p<0.05) following 12 weeks of simvastatin therapy.

However, for those also taking vitamin D the decline was cut to 0.6%. Similarly, skeletal muscle mitochondrial content decreased by 3.6% with simvastatin, but improved by 12.1% with supplementation of vitamin D.

"Our study suggests a decline in exercise-mediated cardiorespiratory fitness and mitochondrial content with the use of simvastatin in patients with type 2 diabetes mellitus, which mitigates by making them vitamin D repleted. Vitamin D replacement alone in deficient individuals improves cardiorespiratory fitness and skeletal muscle citrate synthase activity,” ​wrote the researchers in the Journal of Diabetes​.

“Impaired mitochondrial function has been well demonstrated in skeletal muscles of patients with type 2 diabetes. Interventions targeting mitochondria can provide new tools in our armamentarium to treat diabetes and its complications,”​ they added.

They concluded that due to the increasing use of statins for patients with type 2 diabetes, plus the high prevalence of vitamin D deficiency, large prospective studies were now merited to understand the definitive role of vitamin D in patients on statin therapy.